Electronic components include electronic devices, such as field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), and other integrated circuits, supported on a printed circuit board (PCB). These electronic devices are manufactured on semiconductor substrates by sequential processing operations. Multiple electronic devices can be manufactured on a single substrate. These multiple electronic devices on the single substrate are sliced into multiple dies (or chips) after the sequential processing operations are completed and all the devices are formed. Prior to being placed on the PCB, these electronic devices (or dies) are placed in packages to allow the devices to be handled and to be electrically coupled to the PCB. There are vias and interconnects (wires) embedded in multiple substrate layers in packages that provide an electrical network for the die to be electrically coupled to the PCB and to enable access to other devices. The packaged dies are then disposed on the PCB through metallic connections, such as a ball grid array (BGA) or other suitable packaging configurations.
In high-speed multi-layer package design, efforts have been focused on optimizing the horizontal transmission lines to reduce signal distortion or loss. Little attention has been paid to the vertical transition, which includes micro-via to plated through hole (PTH) and BGA ball interconnection. With the increase in number of layers of interconnections and the need to support broader bandwidth, return loss and/or insertion loss caused by vertical transition discontinuity are becoming dominant design concerns.
Therefore, there is a need for methods of designing vertical transmission lines for optimal signal transition in multi-layer BGA packages.